Parallel capacitor fault repair

What to do if a capacitor fails?

Even if the appearance of the failed capacitor is not abnormal, care must be taken when handling the capacitor. In particular, take care to avoid electric shock *1 due to residual charge on the capacitor, contact of electrolytic solution *2 with the skin or eyes, and inhalation of electrolytic solution vapors.

What causes a capacitor to fail?

And it depends on the type of capacitor, but factors that can cause open failures include vibration and shock during mounting on the board and transportation, as well as placement of the device on the board. When a capacitor fails a short circuit (Figure 3), DC current flows through the capacitor and the shorted capacitor behaves like a resistor.

What happens if you don't replace an electrolytic capacitor?

The capacitor may be worn out, and continued use without replacement may result in an open failure or short circuit. Snap mount type aluminum electrolytic capacitors are used in power supply devices. The heat sink and the top of the capacitor were placed close together to reduce the thickness of the device.

What happens if a capacitor is ruptured?

The pressure-relief vent *9 of an aluminum electrolytic capacitor used for smoothing the power circuit was ruptured and a capacitor started smoking. When the internal pressure of the capacitor rises, the pressure valve opens and electrolyte (gas) is released.

Where is the damaged nwell capacitor located?

See Fig. 11. The damaged NWell capacitor is located in the antenna detection circuitry wherein the top plate is connected to the antenna calibration and switch circuitry while the bottom plate is connected to ground (GND). See Fig. 12.

What is the failure rate of a capacitor?

The failure rate of capacitors can be divided into three regions by time and is represented by a bathtub curve as shown in Figure 37. (1) Early failures *31 exhibits a shape where the failure rate decreases over time. The vast majority of capacitor's initial defects belong to those built into capacitors during processing.